Air Canada B763 over Japan on Mar 15th 2014, acrid smell in aft lavatory

An Air Canada Boeing 767-300, registration C-FCAE performing flight AC-64 from Seoul (South Korea) to Vancouver,BC (Canada) with 169 people on board, was enroute at FL310 about 110nm north of Osaka (Japan) when the crew descended the aircraft to FL300, turned around and returned to Seoul due to an acrid smell in an aft lavatory. The aircraft landed safely in Seoul about 90 minutes later.

The aircraft was able to depart Seoul again after about 90 minutes on the ground and reached Vancouver with a delay of 4 hours.

The Canadian TSB reported the L2 lavatory light socket was replaced.